Sensing arrangements for medical devices

ABSTRACT

A sensing arrangement for a medical device includes a housing having a rigid portion and a flexible portion, a collar of the flexible portion attached to an exterior of the rigid portion such that a stem of the rigid portion extends into an interior of the flexible portion. A sensing element is positioned at least partially within a passageway of the rigid portion, with at least one wire extending from the sensing element through the passageway and into the interior of the flexible portion. Front and rear flanges protrude from the flexible portion and are adapted to allow the sensing arrangement to be attached into an aperture in a wall of the medical device. The stem of the rigid portion may be positioned between the collar and front flanges of the flexible portion, such that the stem does not extend through the aperture of the wall of the medical device. There are also provided a seal, a removable component, a medical device and a system.

PRIORITY

This application is a continuation of U.S. patent application Ser. No.16/466,263, filed Jun. 3, 2019, which is a 371 of PCT Application No.PCT/NZ2017/050157, filed Dec. 7, 2017, which claims priority to U.S.Provisional Patent Application No. 62/431,372, entitled “SensingArrangements for Medical Devices,” and filed Dec. 7, 2016, the entirecontents of which are hereby incorporated by this reference.

BACKGROUND Technical Field

The present disclosure generally relates to devices and methods forproviding heated and/or humidified gases to a user. More particularly,certain features, aspects and advantages of the present disclosurerelate to a sensing arrangement for a medical device such as arespiratory humidification system, a positive airway pressure system, ahigh flow system, an insufflation system and/or a ventilator.

Description of the Related Art

A sensing arrangement for a medical device may include a feature toprovide, in whole or in part, for positioning of the sensingarrangement; for example, the sensing arrangement may include a moreflexible component to allow alignment tolerance between a sensingelement of the sensing arrangement and a desired measurement position ororientation. A sensing arrangement for a medical device may include afeature to provide, in whole or in part, for protection of the sensingarrangement; for example, the sensing arrangement may include a morerigid component to protect the sensing arrangement from damage caused byforces exerted against the sensing arrangement during use.

However, a sensing arrangement for a medical device may include multiplepositioning and/or protection features that may conflict with eachother; for example, a more flexible component that improves positioningof the sensing arrangement may reduce protection of the sensingarrangement, and a more rigid component that improves protection of thesensing arrangement may detract from positioning of the sensingarrangement. There is a need for a sensing arrangement for a medicaldevice that includes features to collectively provide for positioningand protection of the sensing arrangement.

BRIEF SUMMARY

A sensing arrangement for a medical device is disclosed that includesfeatures to collectively provide for positioning and protection of thesensing arrangement.

According to at least one aspect of the present disclosure, a sensingarrangement for a medical device includes one, some, or all of thefollowing features, as well as other features described herein. Thesensing arrangement includes a housing. The housing includes a rigidportion and a flexible portion. The rigid portion includes a tip and astem. An exterior of the rigid portion extends from the tip to the stem.The flexible portion includes a collar region and a tail region. Anexterior of the flexible portion extends from the collar region to thetail region. A rear flange protrudes from the exterior of the flexibleportion in the tail region. A front flange protrudes from the exteriorof the flexible portion between the collar region and the rear flange. Athroat region of the exterior of the flexible portion is between thefront flange and the rear flange. An interior of the flexible portionextends from the collar region to the tail region. The collar region isattached to the exterior of the rigid portion between the tip and thestem. The stem may be positioned within the interior of the flexibleportion between a first plane passing through the collar region and asecond plane passing through the throat region. The stem mayalternatively be positioned within the flexible portion between a firstplane passing through the tail region and a second plane passing throughthe throat region.

The sensing arrangement can include an interior passageway of the rigidportion. The interior passageway can extend from the tip to the stem. Asensing element can be positioned at least partially within the interiorpassageway at the tip.

The sensing arrangement can include at least one wire. The at least onewire can be attached to the sensing element. The at least one wire canextend through the interior passageway to the stem and into the interiorof the flexible portion.

The collar region may be configured to roll over a portion of the rigidportion as the rigid portion moves axially. The collar region maycomprise a curved region that is configured to roll over an attachmentregion, the attachment region being the region where the flexibleportion connects to the rigid portion. Preferably, through forming ofthe collar region from a resilient material, or some other manner suchas an external biasing means, on insertion of the sensing arrangementthrough an aperture, in, for example, a chamber, the collar regionremains partially compressed. This can aid in establishing the correctorientation of the sensing arrangement and improve sealing about saidaperture by increasing the force between a seal and the wall definingthe aperture. Further, this spring force can assist in disengaging thesensing arrangement from the wall about the aperture through itstendency to push against said wall, performing an “auto-eject” function.Thus, for example, a chamber may be locked in position against a heaterbase with the collar region partially compressed. When the lock isreleased, the chamber is then biased away from the sensing arrangementand the base, facilitating removal. Of course, this assumes that thesensing arrangements extend in a direction that opposes the direction inwhich the chamber is slid into engagement with the heater base althoughother arrangements are possible including slidable mountings for thesensing arrangement(s).

The collar region is preferably thicker than the throat region.

The rear flange may have a height that is three quarters or more than aheight of a baffle, wherein the baffle is arranged on a wall of a heaterbase or a wall of a removable component that is adapted to couple to theheater base.

The wall of the heater base or the removable component may include apair of baffles that are spaced apart from each other, the rear flangebeing received between the baffles to prevent rotation of the rearflange.

The sensing arrangement may include one or more seals, the sealsengaging the housing in use to protect the housing and a sensorassociated with the housing. The one or more seals may have a targetregion that contacts the sensor in an operative position. The targetregion may be substantially planar. A width of the target region may be90% or more of the width of an opening in the seal, wherein the openingis configured to receive the housing and sensor within it.

The seal may comprise a cap portion, said target portion forming atleast part of the cap portion, the cap portion comprising at least aportion configured to stretch when the housing and sensor within it isreceived therein.

The housing may comprise a sealing flange provided between the tip andthe collar region, the sealing flange for sealingly mating with the sealat an end thereof distal from the target region. The sealing flange mayprotrude from the exterior of the rigid portion.

The seal may define an internal passageway that is closed at a firstend, said first end being formed at least in part by the target region,wherein, at rest (with the seal not being stretched by the housing), alength of said passageway is less than a length of the housing betweenthe tip and the sealing flange. According to this embodiment, the sealis preferably configured to stretch such that a second end of the sealcontacts the sealing flange when in an operative position with thehousing received inside the passageway, the second end being distal fromthe first end and defining an opening into the passageway.Alternatively, the passageway may be substantially the same length asthe portion of the housing received therein when in an operativeposition for sensing. According to such embodiments, the seal may or maynot be configured to stretch. The stretching of the seal canadditionally or alternatively perform an “auto-eject” function by urgingthe sensing arrangement away from, for example, a chamber.

At least part of the flexible portion may be resiliently deformableand/or act as a spring or resilient member such that the rigid portionis urged towards a rest position.

According to another aspect, a sensing arrangement for a medical deviceincludes a housing for supporting a sensor, the housing including aflexible portion that is resiliently deformable and/or acts as a springor resilient member. Other, preferred features of this aspect may betaken from the other aspects and the description of the preferredembodiments.

According to another aspect, there is provided a removable component fora medical device comprising a sensing arrangement according to any ofthe preceding aspects. The removable component may comprise a wallhaving an aperture therein, the aperture being configured to receive atleast a portion of the housing of the sensing arrangement therein. Theaperture is preferably dimensioned to receive the housing such that thewall is positioned between the rear flange and the front flange.

The removable component may be configured to permanently or removablycouple to said medical device. The coupling may comprise a structuralcoupling, fixing the removable component in position relative to themedical device. The coupling may additionally or alternatively comprisean electrical and/or communicative coupling for enabling signals fromsensor(s) of the sensing arrangement, or data derived therefrom, to becommunicated to the medical device and/or for components of the sensingarrangement to be electrically powered and/or for other communicationsto be exchanged with the removable component such as configuration data.

According to another aspect, there is provided a medical devicecomprising a sensing arrangement and/or a removable component accordingto any one or more of the previous aspects.

The medical device may comprise a heater base, the heater base beingconfigured to receive a liquid chamber and heat the contents thereof.Upon engagement of the chamber with the heater base, at least a portionof the housing of the sensing arrangement may be received in an aperturein the chamber, said aperture preferably being provided in an inlet portor an outlet port of the chamber.

The medical device may comprise, or be adapted to fluidly couple to, agases source. The gases source may, for example, comprise a blower orventilator.

According to another aspect, there is provided a seal for use withapparatus of any one or more of the prior aspects. The seal preferablycomprises a base portion joined to a cap portion by an inset region, theseal defining a passageway, the passageway being open at a first end atthe base portion for receiving at least a portion of a housing of asensing arrangement therein.

Preferably, the seal is closed at a second end at the cap portion. Theinset region may be configured to be received inside an aperture in awall with the cap portion on a first side of the wall and the baseportion on the other, second side of said wall, said sensing arrangementbeing adapted to sense a parameter of a gas on the first side of thewall.

The seal may comprise a target region that contacts a sensor of thesensing arrangement. The target region may be substantially planar. Thewidth of the target region may be 50%, preferably 70% and morepreferably 90% or more of the width of an opening in the seal, whereinthe opening is configured to receive the housing and sensor within it.

The target portion may form at least part of the cap portion. The capportion may comprise at least a portion configured to stretch when thehousing and sensor within it is received therein.

The housing may comprise a sealing flange provided between the tip andthe collar region, with the base portion being configured to sealinglymating with the sealing flange.

According to another aspect, there is provided a humidification chamberadapted for use with the apparatus of any one or more of the prioraspects. More particularly, said chamber may comprise one or moreapertures, preferably in ports thereof, for receiving one or moresensing arrangements therethrough, or at least sensing portions orprobes thereof.

According to another aspect there is provided a system comprisingapparatus according to any one or more of the prior aspects. The systemmay also comprise any one or more of a supply tube, a delivery tube, anexpiratory tube, a patient interface, a liquid chamber.

According to embodiments of the above aspects, a sensing arrangement, orat least a sensing portion thereof, may be adapted so as to be insertedinto an aperture in an inlet port or an outlet port of a chamber,particularly a humidification chamber. However, apertures may bepositioned elsewhere, depending on where it is desired to perform thesensing. Further, more than one aperture may be provided adjacent oneanother, such as in the inlet port and/or the outlet port, each beingpositioned and configured to receive at least one sensing arrangementtherethrough. A said aperture may be configured to receive more than onesensing arrangement therethrough and/or more than one sensing portion ofthe same sensing arrangement. As will be appreciated, particularly wheresensing arrangements or portions or probes thereof are provided in closeproximity, such as at the same port of a chamber, it may be desirable toprovide common components of or integration between the sensingarrangements. Thus, rather than there necessarily being a separatesensing arrangement provided for each sensor supported by the sensingarrangement, the same sensing arrangement may have more than one sensingportion or probe extending therefrom, each supporting a sensor. Further,each sensing arrangement (or portion or probe) may include more than onesensor.

Additionally or alternatively, sensing arrangements may interface withthe gases elsewhere along their path, such as via aperture(s) providedin other positions on the chamber (e.g. the main sidewall or the top),along one of the tubes used to convey gases between the gases source andthe patient interface, the patient interface or cuff connectors used tosealingly connect components of the system together. Further, it will beappreciated that the sensing arrangement could also be used to senseparameters of a liquid, such as the liquid in a humidification chamber,were it considered desirable to do so.

According to some embodiments applied to a humidification chamber, oneor two apertures may be provided in an inlet port each for receiving arespective one or more sensing arrangements or at least a sensingportion or probe thereof. Additionally, or alternatively, one or twoapertures may be provided in an outlet port of a chamber, each forreceiving a respective one or more sensing arrangements or sensingportion or probe thereof. According to a presently preferred embodiment,temperature is measured at an inlet port and an outlet port of a chamberand flow is measured at one or both of the ports, preferably the outletport. Respective seals as described herein may be provided for each saidaperture. Where adjacent apertures are provided, a single seal may beprovided to seal both apertures. For example, base portions of the sealmay be linked via a web. Additionally, or alternatively, a single sealmay be configured to receive more than one sensing arrangement (or atleast sensing portion or probe thereof) and sealing mate with a singleaperture, such as in a port of a chamber. Again, this may, for example,be effected using a web joining base portions of the seals.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example embodiment of a medical system thatincludes a medical device.

FIG. 2A illustrates an example embodiment of the medical device of FIG.1.

FIG. 2B illustrates an enlargement of a portion of the medical device ofFIG. 2A including an example embodiment of a sensing arrangement.

FIG. 3 illustrates a side cross-sectional view of an example embodimentof the sensing arrangement of FIG. 2B.

FIG. 4 illustrates a side cross-sectional view of an example embodimentof the sensing arrangement of FIG. 2B.

FIG. 5 illustrates a cut-away rear view of the sensing arrangement ofFIG. 4 attached to the medical device of FIG. 2A.

FIG. 6 illustrates a side cross-sectional view of an example embodimentof the seal of FIG. 2B and a portion of an example embodiment of thesensing arrangement of FIG. 2B.

FIG. 7 illustrates a side cross-sectional view of an example embodimentof the seal of FIG. 2B and a portion of an example embodiment of thesensing arrangement of FIG. 2B.

FIG. 8 illustrates a side cross-sectional view of an example embodimentof the seal of FIG. 2B with the seal in a first, rest position or state.

FIG. 9 illustrates a side cross-sectional view of the seal of FIG. 8 ina second, operative position or state.

DETAILED DESCRIPTION

Certain embodiments and examples of housings for medical devices aredescribed herein. Those of skill in the art will appreciate that thedisclosure extends beyond the specifically disclosed embodiments and/oruses and obvious modifications and equivalents thereof. Thus, it isintended that the scope of the disclosure should not be limited by anyparticular embodiments described herein.

FIG. 1 schematically illustrates an example embodiment of a medicalsystem 100 that can be used to deliver gases to a patient or other user.The medical system 100 can be used, in some applications, to providerespiratory therapy, including but not limited to invasive ventilation,non-invasive ventilation, positive pressure therapy, or high flowtherapy, or to provide gases for surgical procedures, including but notlimited to laparoscopic or open site surgical procedures.

An example embodiment of the medical system 100 can include a medicaldevice 140 adapted to condition gases, for example to heat and/orhumidify gases, to be delivered to a patient or other user. The medicaldevice 140 can include a base 130 and a chamber 120. The base 130 caninclude a heater 125. The chamber 120 can include an inlet port 115 andan outlet port 150. A supply tube 110 can provide fluid communicationfrom a gases source 105 to the inlet port 115. A delivery tube 155 canprovide fluid communication from the outlet port 150 to a patientinterface 160. The system 100 of FIG. 1 is shown as also including anexpiratory tube 170 connecting between the patient interface 160, viawye piece 180, and the gases source 105. According to some embodimentsthe expiratory tube may be omitted with surplus and exhaled gases beingvented to ambient air and/or directed elsewhere. More generally, theinvention is not limited to any particular arrangement of the pneumaticcircuit.

In an embodiment, the chamber 120 is adapted to be removably mounted onthe base 130 adjacent to the heater 125. Gases supplied by the gasessource 105 flow through the supply tube 110 into the chamber 120 via theinlet port 115 and from the chamber 120 via the outlet port 150 throughthe delivery tube 155 to the patient interface 160. In an embodiment, aliquid 145 contained in the chamber 120 can be heated by the heater 125when the chamber 120 is mounted on the base 130 to heat and/or humidifythe gases flowing through the chamber 120. In an embodiment, acontroller 135 is adapted to control power delivered to the heater 125.

FIG. 2A illustrates an example embodiment of the medical device 140, andFIG. 2B illustrates an enlargement of a portion 210 of the medicaldevice 140 illustrated in FIG. 2A. The base 130 can include a sensingarrangement 235. In an embodiment, the sensing arrangement 235 can beattached into an aperture 245 of a wall 240 of the base 130. In anembodiment, the base 130 includes a removable component 205 thatincludes the wall 240, such that the sensing arrangement 235 is attachedto the removable component 205. The removable component 205 can be acartridge that can removably connect to the base or base unit 130. In anembodiment, the sensing arrangement 235, or at least a sensing portionor probe of the sensing arrangement 235, can be positioned to beinserted into an aperture 225 on the inlet port 115 of the chamber 120when the chamber 120 is mounted on the base 130.

A sensing arrangement 235, or at least a sensing portion thereof, mayadditionally or alternatively be positioned to be inserted into anaperture of the outlet port 150. Further, more than one aperture may beprovided in the inlet port 115 and/or the outlet port 150, each beingpositioned and configured to receive at least one sensing arrangement235 therethrough. For the avoidance of doubt, an aperture in the inletport 115 and/or outlet port 150 may be configured to receive more thanone sensing arrangement 235 therethrough and/or more than one sensingportion of the same sensing arrangement. As will be appreciated,particularly where sensing arrangements 235 or portions or probesthereof are provided in close proximity, such as at the same port 115,150, it may be desirable to provide common components of or integrationbetween the sensing arrangements 235. Thus, rather than therenecessarily being a separate sensing arrangement 235 provided for eachsensor supported by the sensing arrangement 235, the same sensingarrangement 235 may have more than one sensing portion or probeextending therefrom, each supporting a sensor. Further, each sensingarrangement 235 (or portion or probe) may include more than one sensor.

Additionally or alternatively, sensing arrangements 235 may interfacewith the gases elsewhere along their path, such as via aperture(s)provided in other positions on the chamber 120 (e.g. the main sidewallor the top), along one of the tubes used to convey gases between thegases source and the patient interface, the patient interface or cuffconnectors used to sealingly connect components of the system together.

According to one embodiment, a respective at least one (preferably oneor two) sensing arrangement 235 (or sensing portion or probe thereof) isarranged to be received through a corresponding at least one aperture ineach of the inlet port 115 and the outlet port 150. According to oneembodiment, a single sensing arrangement 235 (or sensing portion orprobe thereof) is associated with the inlet port 115, preferably formeasuring temperature, whereas two sensing arrangements 235 (or twosensing portions or probes of the same or different sensing arrangements235) are associated with the outlet port, preferably for measuringtemperature and flow. However, other sensor types may additionally oralternatively be used, dependent somewhat on the particular application.Some examples of these are listed hereinbelow.

In an embodiment, the sensing arrangement 235 is adapted to measure aproperty or characteristic of gases flowing through the inlet port 115and to provide a signal representative of the measured property orcharacteristic to the controller 135. For example, the sensingarrangement 235 may provide a signal to the controller 135 thatrepresents a temperature of gases or flow rate of gases flowing throughthe inlet port 115 past the sensing arrangement 235. In an embodiment,the controller 135 can use the measured temperature, at least in part,to determine an amount of power to deliver to the heater 125. As will beappreciated, the controller may be provided elsewhere with appropriatecommunicative couplings provided for the transfer of data. Further,control may be distributed with processing occurring using more than onecontroller, said controllers being co-located and/or spaced apart, againwith known wired and/or wireless communicative couplings providedtherebetween. The sensors may be used simply to record parameterssensed. Such data may be used, for example, provide information on useof the apparatus for patient compliance purposes. However, morepreferably, the sensed parameters may be used in effecting control ofthe wider apparatus. For example, flow rate may be adjusted or heatingapplied by a heater of the chamber may be varied. Similarly, heatingapplied by a heatable delivery tube may additionally or alternatively bevaried. Where other parameters are monitored such as constituents ofgases delivered, actuators may be controlled to enable the compositionof the gases to change. For example, a valve may be opened to enableadditional oxygen to be fed into the gas stream.

To this end and by way of example only, the sensing arrangement maycomprise any one or more of:

-   -   a thermistor, a thermocouple, a resistance temperature detector        (RTD), thermopile for measuring temperature,    -   a thermistor, heated wire or element, Venturi, anemometer for        measuring flow.    -   a transducer, diaphragm, strain gauge for measuring pressure,    -   a microphone or transducer for measuring noise,    -   a gas concentration and/or composition sensor (e.g. oxygen,        helium, nitric oxide, carbon dioxide sensors),    -   a sensor adapted for systems in which additives, such as        medicaments, are provided to the gases supplied to a patient        e.g. using a nebulizer    -   a pH sensor,    -   an enthalpy sensor,    -   additional or alternative sensors as would be known to one        skilled in the art.

Said sensors and/or said associated processing logic may be adapted tomeasure or derive absolute values of the parameters being monitoredand/or changes therein and/or rates of change therein.

While component 205 is removable according to preferred embodiments, theinvention is not limited to it being so. Rather, the component 205 maybe fixedly or irremovably coupled to the base 130. Alternatively, thecomponent 205 may be formed integrally with the base 130 such thatcomponent 205 is a constituent part of the base 130. Some degree ofremovability of component 205 is preferred since this enables thesensing components to be easily repaired or replaced without having toreplace the entire base 130. Further, it can allow for differentcomponents 205 to be used for different applications. For example, someapplications may involve different operational parameters (temperature,flow, pressure etc.) and the sensors used for each can then be tailoredwithout having to replace the entire base unit 130. Further, for someapplications, different numbers of sensors may be desirable, theremovability again providing for easy adaptation of the system to aparticular application. Further, component 205 may include processinglogic for, at least in part, processing the data received from thesensors. Removability allows for adaptation of the logic for differentapplications by using different components 205 with differentconfigurations (in terms of hardware (e.g. number and/or positions ofsensors) and/or logic) although an alternative on the logic side wouldbe to provide for some form of communicative coupling so that the logiccould be manipulated without removing the component 205 from the heaterbase.

In some embodiments, the chamber 120 includes a seal 215 positioned inthe aperture 225 on the inlet port 115. The seal 215 can include a baseportion 230 adapted to prevent gases from escaping the chamber 120through the aperture 225 when the sensing arrangement 235 is insertedinto the aperture 225. In some embodiments, the seal 215 can include acap portion 220 adapted to separate the sensing arrangement 235 fromgases in the chamber 120 but still allow the sensing arrangement 235 tomeasure a characteristic of the gases through the cap portion 220. Insome such embodiments, some or all of the cap portion 220 may be rigid.In some such embodiments, some or all of the cap portion 220 may beflexible; for example, the sensing arrangement 235 may cause the capportion 220 to stretch when the sensing arrangement 235 is inserted intothe aperture 225 and thus into the seal 215. In some embodiments, theseal 215 may include no cap portion 220, thus allowing the sensingarrangement 235 to directly contact gases in the chamber 120. The sealmay be formed from silicone or any other suitable resilient polymer.

FIGS. 3 and 4 illustrate side cross-sectional views of a sensingarrangement 300 and a sensing arrangement 400, respectively, that areexample embodiments of the sensing arrangement 235 with somesimilarities, as described. The sensing arrangement 300, 400 can includea housing 375, 475 that includes a rigid portion 380, 480 and a flexibleportion 360, 460. The rigid portion 380, 480 can include a tip 305, 405and a stem 355, 455. An exterior 310, 410 of the rigid portion 380, 480can extend from the tip 305, 405 to the stem 355, 455. The flexibleportion 360, 460 can include a collar region 325, 425 and a tail region340, 440. An exterior 370, 470 of the flexible portion 360, 460 canextend from the collar region 325, 425 to the tail region 340, 440. Theflexible portion 360, 460 can include a rear flange 335, 435 protrudingfrom the exterior 370, 470 in the tail region 340, 440; a front flange330, 430 protruding from the exterior 370, 470 between the collar region325, 425 and the rear flange 335, 435; and a throat region 365, 465 ofthe exterior 370, 470 between the front flange 330, 430 and the rearflange 335, 435.

An interior 345, 445 of the flexible portion 360, 460 of the sensingarrangement 300, 400 can extend from the collar region 325, 425 to thetail region 340, 440. The collar region 325, 425 can be attached to anattachment region 320, 420 of the exterior 310, 410 of the rigid portion380, 480 between the tip 305, 405 and the stem 355, 455. A passageway350, 450 of the rigid portion 380, 480 can extend from the tip 305, 405to the stem 355, 455. A sensing element 383 can be positioned at leastpartially within the passageway 350, 450 at the tip 305, 405. At leastone wire 353 can be attached to the sensing element 383. The at leastone wire 353 can extend from the sensing element 383 through thepassageway 350, 450 to the stem 355, 455 and into the interior 345, 445of the flexible portion 360, 460.

As described above with respect to the sensing arrangement 235, thesensing arrangement 300, 400 can be attached to or otherwise provided toor formed with the base 130 and/or the removable component 205. Thethroat region 365, 465 can be positioned within the aperture 245 of thewall 240, so as to position the front flange 330, 430 adjacent anoutside 369 of the wall 240 and to position the rear flange 335, 435adjacent an inside 367 of the wall 240. A sealing flange 315, 415 canprotrude from the exterior 310, 410 of the rigid portion 380, 480between the tip 305, 405 and the attachment region 320, 420. When thesensing arrangement 300, 400 is attached to the base 130, the sealingflange 315, 415 is adapted to contact the base portion 230 of the seal215 when the chamber 120 is mounted on the base 130 (and thus when thesensing arrangement 300, 400 is inserted into the aperture 225 on theinlet port 115).

The collar region 325, 425 of the flexible portion 360, 460 of thesensing arrangement 300, 400 is adapted to allow an external forceexerted against the rigid portion 380, 480 to cause the rigid portion380, 480 to move away from a rest position in response to the externalforce and then return to the rest position in the absence of theexternal force. With respect to the plane of the cross-sectionillustrated in FIGS. 3 and 4, an example of a rest position can berepresented by a line between the tip 305, 405 and the stem 355, 455being parallel to a line segment 308 that has an angle α to a linesegment 307 that is parallel to the wall 240.

Discussion follows on example vectors. These are for illustrativepurposes only. The vectors in practice will vary somewhat as the chamberis installed onto or removed from the base. Further, tolerances mayallow for the chamber to be in slightly different positions ororientations when in the rest state with the chamber operably installedon the base. Further still, the base and/or the chamber and/or thesensing arrangement and/or the removable portion may be configureddifferently, still embodying the invention but with different resultantvectors.

An example external force exerted against the rigid portion 380, 480 mayhave an inward component, which is a component of force in the directionof a vector 313 from the tip 305, 405 toward the stem 355, 455 that isparallel to the line segment 308. An inward component of force exertedagainst the rigid portion 380, 480 can cause the collar region 325, 425to compress with a spring force in response to the inward component offorce. When the inward component of force is exerted by the base portion230 of the seal 215 against the sealing flange 315, 415—when the chamber120 is being mounted on the base 130—a spring force produced in responseby the collar region 325, 425 presses the sealing flange 315, 415against the base portion 230 to hold the sensing element 383 in positioninside the cap portion 220 of the seal 215 and, according to preferredembodiments, to cause the cap portion 220 to stretch.

An example external force exerted against the rigid portion 380, 480 mayhave a side component, which is a component of force in the direction ofa vector 311 that has some non-zero angle γ to the line segment 308. Aside component of force exerted against the rigid portion 380, 480 cancause the collar region 325, 425 to flex, allowing the rigid portion380, 480 to move so that the sensing element 383 moves in a directionsimilar to the side component of force—although not in the samedirection, since the attachment of the sensing arrangement 300, 400 tothe wall 240 at the throat region 365, 465 will cause the sensingelement 383 to move following, for example, an arc 309 rather than astraight line.

With regard to FIG. 3, the stem 355 of the sensing arrangement 300 canbe positioned within the interior 345 of the flexible portion 360between a plane passing through the tail region 340 that is normal tothe line segment 308 and a plane passing through the throat region 365that is parallel to the line segment 307 when the sensing arrangement300 is attached into the aperture 245 of the wall 240 and is at rest. Inother words, when the sensing arrangement 300 is attached to the base130, the rigid portion 380 extends through the aperture 245. A sidecomponent of force in the direction of the vector 311 exerted againstthe rigid portion 380 may cause the rigid portion 380 to move such thata line between the tip 305 and the stem 355 is parallel to, for example,a line segment 306 having an angle β to the line segment 308. For asufficiently large angle β, the rigid portion 380 may pinch the flexibleportion 360 in the throat region 365 against the wall 240, which couldcause the flexible portion 360 to weaken or tear.

With regard to FIG. 4, the stem 455 of the sensing arrangement 400 canbe positioned within the interior 445 of the flexible portion 460between a plane passing through the collar region 425 that is normal tothe line segment 308 and a plane passing through the throat region 465that is parallel to the line segment 307 when the sensing arrangement400 is attached into the aperture 245 of the wall 240 and is at rest. Inother words, when the sensing arrangement 400 is attached to the base130 (including via the removable component 205), the rigid portion 480does not extend through the aperture 245. The stem 455 does not extendinto the aperture 245. A side component of force in the direction of thevector 313 exerted against the rigid portion 480 may cause the rigidportion 480 to move such that a line between the tip 405 and the stem455 is parallel to, for example, the line segment 306 having the angle(3 to the line segment 308. Even for a large angle (3, the rigid portion480 will not pinch the flexible portion 460 in the throat region 465against the wall 240. The stem 455 not inserting into the aperture isadvantageous because it reduces the likelihood of the wall 240 acting onthe stem if the sensing arrangement is bent during use. This reducesbending stresses on the stem and thus reduces the chance of the stemfrom breaking and thus reducing the chance of the wire 353 breaking dueto the bending stresses acting through the stem. Still with reference toFIG. 4, the collar portion 425 comprises a shorter radius of an arcportion adjacent the connection portion 420. The shorter radius promotesa rolling behavior of the resilient or flexible portion 460. Theflexible portion 460, by being resiliently deformable, acts as a springor resilient member as the collar portion 425 is moved relative to otherparts of the sensing arrangement. The collar portion 425, and the curvedsection of the collar portion rolls over the attachment region 420 asthe rigid portion 480 is pushed inward toward the aperture 245. Thethickness of the flexible portion 460 is greater at the collar region425 and thinner at the throat region 465. The thicker flexible portion465 at the collar region 425 assists in creating the rolling motion asthe sensor or sensing arrangement is compressed during operation. Thecollar region 425 rolls over the attachment region 420 as the rigidportion moves axially in use. The thickness at the collar region can bebetween 0.5 mm and 1.5 mm, more preferably between 0.8 mm and 1.25 mm,more preferably between 0.86 mm and 1.21 mm. According to someembodiments, the thickness at the collar region can be between 1.05 mmand 1.25 mm. The internal radius of the curved section of the collar 425may be between 0.1 mm and 1 mm, more preferably between 0.3 mm and 0.8mm and more preferably still between 0.4 mm and 0.75 mm. Due to theshorter radius of the collar portion and the increased thickness in thecollar region, a more constant spring force is achieved, a rollingaction is achieved and reduced buckling is achieved as the sensingarrangement (i.e. the rigid portion) is compressed in use. The springforce may be between 0.1N and 15N, more preferably between 0.1N and 10N,more preferably still between 0.3N and 5N, over the force profileapplied to the sensing arrangement. According to some embodiments, thespring force is between 0.5N and 1.5N over the force profile applied tothe sensing arrangement.

The rear flange 435 is shown in FIG. 4 in a relaxed configuration, inother words with no external forces exerted against it. A portion 433(shown shaded in FIG. 4) of the rear flange 435 is positioned such thatwhen the sensing arrangement 400 is attached into the aperture 245 ofthe wall 240, the portion 433 would occupy the same space as the wall240 unless the rear flange 435 bends to move the portion 433 out of theway of the wall 240. Bending causes the rear flange 435 to exert forceagainst the wall 240; for example, an outward component of force exertedby the rear flange 435 against the wall 240 can be in the direction of avector 414. The outward component of force can help to hold the sensingarrangement 400 in position against the wall 240. It can also assist inmoving, the chamber for example, away when desired since this force actsthereon (by the wall thereof being received in the recesses 610, 710—seeFIGS. 6-9).

FIG. 5 illustrates a cut-away view of the wall 240 from inside theremovable component 205, showing the sensing arrangement 400 attachedinto the aperture 245 of the wall 240. The view shown in FIG. 5 couldalternatively be of an aperture in the wall of the base where theremovable component 205 is formed by the base 130. The rear flange 435is positioned to exert force against the wall 240, as described above. Apair of baffles 505 protrude from the inside 367 of the wall 240 oneither side of the aperture 245 such that the rear flange 435 ispositioned between the pair of baffles 505 when the sensing arrangement400 is attached into the aperture 245. The pair of baffles 505 help toprevent rotational movement of the sensing arrangement 400 around theaxis of the line segment 308 by blocking motion of the rear flange 435in directions 510 and 515 that lie in a plane normal to the line segment308. The rear flange 435 may have a height that is more than threequarters the height of the baffles 505. The height of the rear flange435 being greater than three quarters the height of the baffles 505reduces the chances of the rear flange 435 riding up and over thebaffles 505 and allowing rotation of the sensing arrangement. Lesserheights may also suffice, particularly depending on the resiliencyand/or stiffness of the material forming the flexible portion.Essentially, the stiffer or more resilient the material, the more theheight in the baffles can be reduced. Further, the stiffness of theflexible portion may be varied so as to be stiffer in some parts, suchas at the flange 435. For example, different curing parameters may beused for different parts of the flexible portion and/or a rigid or morerigid member may be incorporated into or joined to a portion of theflexible member. For example, a plate-like member could be embedded inor joined to the flange 435 with the result that baffles 505 may have alesser height,

FIGS. 6 and 7 illustrate side cross-sectional views of a seal 600 and aseal 700, respectively, that are example embodiments of the seal 215with some similarities, as described, and side cross-sectional views ofa portion of a sensing arrangement 660 that is an example embodiment ofthe sensing arrangement 235. The seal 600, 700 can include a baseportion 605, 705 and a cap portion 615, 715 that are example embodimentsof the base portion 230 and the cap portion 220, respectively, that aredescribed above. The base portion 605, 705 can be joined to the capportion 615, 715 by an inset region 610, 710. The cap portion 615, 715can include a target region 630, 730, a shoulder region 640, 740, and aside region 620, 720. The shoulder region 640, 740 can surround thetarget region 630, 730 and join the target region 630, 730 to the sideregion 620, 720.

The target region 630, 730 can include an inner target surface 635, 735having a substantially flat profile that is parallel to a planecontaining a vector 633, 733. The side region 620, 720 can include aninner side surface 625, 725 having a substantially flat profile that isparallel to a plane containing a vector 631, 731 that has an angle δ, θto the vector 633, 733. The shoulder region 640, 740 can include aninner shoulder surface 645, 745 having a curved profile that transitionsfrom the plane of the inner target surface 635, 735 to the plane of theinner side surface 625, 725 through the angle δ, θ. A width ω, ψ candefine an extent of the inner target surface 635, 735 that issubstantially flat and parallel to the plane containing the vector 633,733. Within the width ψ, ω, the target region 630, 730 can have asubstantially uniform thickness κ, λ.

The sensing arrangement 660, more particularly the sensing portion orprobe thereof, comprises a sealing flange 665, a rigid portion 655, anda sensing element 650, each having similar properties to the sealingflange 315, 415, the rigid portion 380, 480, and the sensing element383, respectively, of the sensing arrangement 300, 400. The sealingflange 665 is adapted to contact the base portion 605, 705 and thesensing element 650 is adapted to contact the cap portion 615, 715 whenthe sensing arrangement 660 is attached to the base 130 and the chamber120 is mounted on the base 130, as previously described. In anembodiment, the sensing element 650 is adapted to contact the innertarget surface 635, 735 of the cap portion 615, 715 within the width ω,ψ.

In an embodiment, the sensing arrangement 660 (as well as other sensingarrangements described herein) can be calibrated, and the controller 135can be configured, such that the sensing arrangement 660 provides asignal to the controller 135 that accurately represents a desiredtransform of a measurement made by the sensing arrangement 660 throughthe substantially uniform thickness κ, λ of the target region 630, 730.For example, the sensing arrangement 660 can measure a temperature of50.0° C. through the target region 630, 730 of gases in the chamber 120and provide a signal to the controller 135 that the controller 135interprets as 50.0±0.1° C. If the sensing element 650 does not contactthe inner target surface 635, 735—for example, if the sensing element650 instead contacts the inner shoulder surface 645, 745—the sensingarrangement 660 may provide a signal to the controller 135 that does notaccurately represent a desired transform of the measurement made by thesensing arrangement 660.

The shoulder region 640, 740 may have a thickness different from thesubstantially uniform thickness κ, λ of the target region 630, 730,which may cause a measurement made by the sensing arrangement 660through the shoulder region 640, 740 to be inaccurate. Thus, it ispreferred that the sensing element 650 contact the inner target surface635, 735 and not the inner shoulder surface 645, 745. A width π, ρ candefine an extent of a projection of the inner shoulder surface 645, 745onto the plane containing the vector 633, 733, the width π, ρ beinginclusive of the width ω, ψ of the inner target surface 635, 735. Inother words, the π, ρ represents an inner diameter of the cap portion615, 715. The inner shoulder surface 645, 745 itself occupies an annularspace (in projection onto the plane containing the vector 633, 733)around the inner target surface 635, 735, the annular space having aring width (that is, a difference in diameter between concentriccircles) of (π−ω)/2, (ρ−ψ)/2.

In embodiments of the seal 600 and the seal 700 where the cap portion615 and the cap portion 715 share a common inner diameter, such thatπ=ρ, and the inner target surface 735 is wider than the inner targetsurface 635, such that ψ>ω, then (ρ−ψ)/2<(π−ψ)/2, making the ring widthof the inner shoulder surface 745 narrower than the ring width of theinner shoulder surface 645. For example, in embodiments of the seal 600and the seal 700 with π=ρ=3.5 mm, if ψ=3.25 mm and ω=1.5 mm, then thering width of the inner shoulder surface 645 is (π−ω)/2=1.0 mm and thering width of the inner shoulder surface 745 is (ρ−ψ)/2=0.13 mm.Considered another way, in this example, the width of the inner targetsurface 635 represents ω/π=43% of the width of the combination of theinner target surface 635 and the inner shoulder surface 645, whereas thewidth of the inner target surface 735 represents ψ/ρ=93% of the width ofthe combination of the inner target surface 735 and the inner shouldersurface 745. The increased inner target surface region provides agreater area for the sensor tip to engage an optimal sensing region ofthe seal.

According to some embodiments, widths π and ρ are greater than 0 mm andless than or equal to 20 mm. more preferably between 2 mm and 15 mm andmore preferably between 4 mm and 10 mm. Widths ω and ψ may be less than15 mm, more preferably less than 10 mm and more preferably less than 8mm. Thicknesses κ and λ may be less than 2.5 mm, preferably less than 2mm and more preferably less than 1.5 mm.

FIGS. 8 and 9 show an alternative embodiment. In FIG. 8, the sensingelement 650 has been partially inserted into the seal 600. In thisposition, the seal is at rest i.e. not subject to force by the housingfrom the tip contacting the target region but held in position with theinset region received inside the aperture defining the port and the baseportion and the cap portion of the seal on either side of the walldefining the aperture.

FIG. 9 shows the sensing portion 650 more fully inserted into the seal600, into an operative position for sensing, a configuration which wouldresult, for example, from the chamber being fully, or near fully,operably installed on the base. According to the embodiment of FIGS. 8and 9, at least a portion of the seal 600 is elastically deformable suchthat as the sensing element 650 is inserted, a portion of the wallforming the seal thins. Preferably, said at least a portion that iselastically deformable comprises at least the target portion 635. Sincethe sensing element is configured to sense in the target portion 635,the thinning of the wall in that region enables more accuratemeasurements to be taken while still isolating and protecting thesensing element from the environment to be sensed. However, at the earlystages of insertion, where movement is less constricted or controlled,the wall is relatively thick, better preventing tearing etc.

Additional or alternative parts of the seal may be elasticallydeformable. More preferably, the seal may be integrally moulded from asingle, elastically deformable material, such as a silicone or any othersuitable resilient polymer, such that the entire seal is resilientlydeformable.

In the at rest or unstretched configuration shown in FIG. 8, thethickness t in the target region may be less than 2.5 mm, preferablyless than 2 mm and more preferably less than 1.5 mm. and reduce to below1.5 mm, preferably less than 1 mm or 0.5 mm when stretched as shown inFIG. 9. Similarly, in the at rest or unstretched configuration shown inFIG. 8, the length of the interior passageway of the seal (i.e. from theunderside or inside of the target region to the bottom of the baseportion) id less than 50 mm in the at rest position in FIG. 8,preferably less than 30 mm and more preferably less than 15 mm. Thislength may increase to up to 50 mm in the stretched configuration shownin FIG. 9, preferably up 35 mm and more preferably up 20 mm.

The foregoing description of the invention includes preferred formsthereof. Modifications may be made thereto without departing from thescope of the invention. To those skilled in the art to which theinvention relates, many changes in construction and widely differingembodiments and applications of the invention will suggest themselveswithout departing from the scope of the invention as defined in theappended claims. The disclosures and the descriptions herein are purelyillustrative and are not intended to be in any sense limiting.

1. (canceled)
 2. A seal for use with a sensing arrangement, the seal comprising: a base portion at a first end; a cap portion at a second end; and, a planar target portion configured to contact a sensor of the sensing arrangement in use, the target portion forming at least part of the cap portion.
 3. The seal of claim 2, wherein the second end is distal from the first end and the seal is closed at the second end.
 4. The seal of claim 2, wherein the base portion is joined to the cap portion by an inset region and the cap portion comprises a shoulder region and a side region, the shoulder region surrounding the target portion and joining the target portion to the side region.
 5. The seal of claim 2, wherein the target portion has a substantially uniform thickness.
 6. The seal of claim 2, wherein base portions of the seal may be linked via a web.
 7. The seal of claim 2, wherein the seal defines a passageway comprising an opening at the first end for receiving at least a portion the sensing arrangement.
 8. The seal of claim 2, wherein the cap portion comprises at least a portion that stretches.
 9. The seal of claim 2, wherein a width of the target portion is 90% or more of the width of an opening in the seal, wherein the opening is configured to receive the sensing arrangement.
 10. A medical device comprising: the seal of claim 7; and a sensing arrangement, the sensing arrangement comprising a housing and a sensor.
 11. The medical device of claim 10, wherein the sensing arrangement is calibrated, and provides a signal to a controller that represents a desired transform of a measurement made by the sensing arrangement through a substantially uniform thickness of the target portion.
 12. The medical device of claim 10, wherein the housing of the sensing arrangement comprises: a sealing flange; a rigid portion comprising at least a tip; and a flexible portion comprising at least a collar region, the sealing flange being provided between the tip and the collar region, the sealing flange for sealingly mating with the seal at the first end.
 13. The medical device of claim 12, wherein the sealing flange protrudes from an exterior of the rigid portion.
 14. The medical device of claim 12, wherein a rear flange protrudes from an exterior of the flexible portion, the rear flange having a height that is three quarters or more than a height of a baffle, wherein the baffle is arranged on a wall of a heater base or a wall of a removable component that is adapted to couple to the heater base.
 15. The medical device of claim 12, wherein, at rest, a length of the passageway is less than a length of the housing between the tip and the sealing flange.
 16. The medical device of claim 12, wherein, at rest, a length of the passageway is substantially equal to a length of the housing between the tip and the sealing flange.
 17. The medical device of claim 12, wherein the seal stretches such that the first end of the seal contacts the sealing flange when in an operative position with the housing received inside the passageway.
 18. The medical device of claim 12, wherein at least part of the flexible portion is resiliently deformable and acts as a spring or resilient member such that the rigid portion is urged towards a rest position.
 19. The medical device of claim 12, further comprising a humidification chamber to hold liquid, wherein stretching the seal urges the sensing arrangement away from the humidification chamber.
 20. The medical device of claim 19, wherein the humidification chamber comprises one or more apertures provided in an inlet port or outlet port for receiving one or more sensing arrangements or at least sensing portions or probes of the one or more sensing arrangements.
 21. The medical device of claim 19, wherein the seal receives one or more sensing arrangements or at least sensing portions or probes of the one or more sensing arrangements.
 22. The medical device of claim 20, wherein the one or more apertures comprise at least two apertures, wherein the at least two apertures are adjacent to each other.
 23. The medical device of claim 22, wherein the seal seals the at least two apertures. 